1. Field of the Invention
This invention relates to a valve which can be opened to allow fluids to pass therethrough and more particularly, but not solely, to valve or so-called water key for a musical wind instrument, which can be opened to drain saliva from within the instrument.
2. Related Background Art
Musical brass wind instruments comprise elongate lengths of pipe work extending from the mouthpiece. These pipes are formed into various coils and bends, depending on the type of instrument.
When playing a brass instrument, it is common for saliva to pass from the musicians's mouth into the pipe work, where it collects at the lowermost point of one of the bends or coils. The collection of saliva affects the performance of the musical instrument and is undesirable.
In order to overcome this problem it is well known to provide a so-called water key on brass instruments, which can be opened to drain the saliva. Such water keys generally comprise an annular collar braised to the outside of the pipe work around an aperture, formed on the underside of a point on a bend or coil of the pipe work, which is lowermost when the instrument is being played.
A disc having a pad of resiliently compressible material, such as cork, on its underside is mounted over the collar on an elongate arm which extends longitudinally of the pipe. The arm is pivoted intermediate its opposite ends to a support member which is also braised to the pipe work.
The opposite end of the arm is enlarged to provide a surface which can be depressed to lift the disc away from the apertured collar and thereby allow the collected saliva to pass therethrough. A spring biases the arm into a position where the disc is normally held against the collar.
The shape of the arm and disc assembly is such that it generally has to be formed of a metal casting. However, this is costly to produce.
The resilient pad on the disc is prone to wear and over time, the pad provides an imperfect seal and allows air to escape from the pipe whilst the instrument is in use. It will be appreciated that this affects the performance of the instrument.
Another disadvantage is that the spring often breaks or becomes disengaged, thereby allowing the disc to move away from the apertured collar and again allowing air to escape.
Yet another disadvantage is that the support has to be attached to the pipe work and thus is difficult and time consuming to achieve.
Thus, known water keys are complicated and expensive in construction and work unreliably.